The present invention relates to agricultural windrowers and, more particularly, to a mechanism for guiding a windrower through a field while making an initial cut in order to create merged windrows.
A windrower typically consists of a self-propelled tractor or similar vehicle, and a cutting mechanism which is either towed by the tractor or carried thereby. The cutting mechanism carried by a windrower is typically referred to as a header, and is supported on the windrower by forwardly projecting arms. Current practice in agriculture is to cut a relatively wide swath of the crop within a range of anywhere between 10 and 19 or more feet in width, and then consolidate the crop into a narrower, substantially continuous windrow, in which form the crop is left to dry in the field until the moisture content has been reduced to a value suitable for subsequent harvesting operations, such as baling or chopping.
More current practice is to combine multiple windrows together as they are being mowed. This practice eliminates a raking operation and also reduces the number of passes of subsequent harvesting operations (e.g., chopping and baling). With the advent of higher capacity forage harvesters and balers, merging windrows has become more desirable than increasing windrower header widths as a means to keep pace with the higher capacity machines used in subsequent harvesting operations. Windrow merging attachments are thus becoming more prevalent on windrowing machines.
Merging two windrows requires the windrower to make an initial pass through a field and then make a second pass adjacent to the first pass but in the opposite direction. Often two passes do not provide sufficient crop material in the merged windrow to satisfy the capacities of larger forage harvesters and balers; therefore, merging the windrows of three or four windrowing passes may be desired. Merging three windrows requires making an initial pass through a field while leaving areas of uncut crop on both sides of the windrower. During the initial pass, the merger apparatus is positioned to allow the windrow to fall directly behind the windrower. Subsequent additional passes, one on each side of the initial pass, are then performed with the merger apparatus directing the windrow toward the centrally located initial windrow. For even larger windrows, it may be desirable to merge four windrows together. This is performed in a manner that similarly requires an initial pass through the field with uncut crop on both sides of the windrower. An initial pass and a subsequent adjacent pass are performed while limiting the merger apparatus discharge distance so that a merged windrow is formed along the boundary of the first two passes. Two additional passes are them performed, one on either side of the double swath formed by the first two passes, with the merger discharge apparatus configured for a greater discharge distance and the windrows directed to the centrally positioned merged windrow from the first two passes. A problem arises in guiding the windrower on the initial pass through the uncut crop so that the distance from the header end to the edge of the previously uncut crop is consistently equal to the cutting width of the header. If the initial pass is too close to the edge of the uncut crop, the subsequent second pass will not fully utilize the windrower capacity. If the initial pass is too far from the edge of the uncut crop, the uncut crop for the subsequent second pass will be too wide and result in standing crop left in the field. GPS systems have been recently employed to aid in initial swath path guidance. However, these systems require a significant investment and are not economical for all customers.
It would be a great advantage to provide a simple mechanism to assist an operator in guiding a windrower while making an initial pass of a multiple-pass windrow merging operation such that subsequent passes would encounter optimal widths of standing crop thereby overcoming the above problems and disadvantages.